Grinding and pulverizing apparatus.



No. 849,545. A PATENTED APR. 9, 1907. B. HUNT. GRINDING AND PULVERIZING APPARATUS.

APPLICATION FILED FEB. 27.1908.

W SS SP lnvenl'ozz- BERTRAM HUNT, OF SAN FRANCISCO, CALIFORNIA.

GRINDING AND PULVERIZING APPARATUS.

Specification of Letters Patent.

Patented April 9, 1907.

1 pplication filedlPebruaryiZZ 19061 Serial No. 308,189.

To all whom it may concern.-

Be it known that I, BERTRANI HUNT, a subject of Great Britain, residing at San Francisco, county of San Francisco, and State of California, have invented certain new and useful Improvements in Grinding and Pulverizing Apparatus; and I hereby declare the following to be a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming a part of this specification.

This invention relates to means for grinding and pulverizing substances, especially l i l i l I i l l l i minerals, such as auriferous or other ores, by

agitation and attrition, and to certain useful improvements 1n machines and apparatus for that purpose, as hereinafter described,

explained, and illustrated by drawings that form a part of this specification.

My improvements consist in confining and moving the abrading agent, commonly pebbles, metallic balls, or the like, between revolving and fixed or relatively moving surfaces disposed in a horizontal plane, so that both the pressure thereon and the rate of ,movement will be under control.

The objects of my invention are to increase the action of the abrading agent, as hitherto employed in tube-mills, .tumbling barrels, and like machines, by an improved construction permitting pressure of the superincumbent mass on the abrading agent and, the substance to be ground or pulverized, also to attain rapid motion of the abrading agents and consequent increase of effect and of the amount of work that can be performed in a given time and in proportion to the cost, Weight, and dimensions of the machinery employed.

To these ends I construct grinding and pulverizing machines substantially as shown in the drawings, such construction'being especi ally adapted for finely-comminuted mineral ores, Figure I being a vertical section through a simple machine to operate according to my invention, and Fig. II a plan view of the device shown in Fig. I with the superposed parts omitted.

In grinding and pulverizing by means of free-moving agents-such as gravel, pebbles, metallic balls, or the like, amon which the material to be treated is difi'useiI there are in the horizontal machinery now in use two defects that limit the amount of work performed and increase the cost and extent of thelmachinerylemployed. These 'defectsgare a want of means to produce pressure between the rubbing or abrading surfaces and the limitation of speed. which cannot exceed what will permit the.abrading material to fall by gravity against centrifugal force. I do not in this remark respecting pressure include crushing-machines operating with balls or rollers having superposed weight thereon, but refer to that class that operate by attrition, as in the type of machines already named.

To attain an increased 'efliciency and reduce the dimensions of machines operating by attrition, I provide a construction substantially as shown in the drawings, now to be referred to.

1 is a main casing of cylindrical form, shown with vertical walls, but which can be made divergent or flaring.

2 is a revoluble agitating device, hereinafter called the driver, supported on a shaft 3, held in bearings 4 and 5, having suitable supports and driven by the wheels 7 and v 8, power being applied to the shaft 9. This constitutes what is called a top-driving arrangement; but it will be understood that thedriver 2 can be operated from beneath the machine by extending the shaft 3 down through the bottom of the casing 1, both these forms of construction being common in practice.

The driver 2 consists of hollow hub 10, with an annular passage 12 for ore or other material to be ground, that is supplied from a spout 13 or in other suitable manner. To the hub of the driver 2 is attached a series of arms or vanes 14, that stir and agitate the filling or abrading material 18, which is, by preference, coarse gravel or pebbles of hard stone.

On the bottom of the main casing 1 are fastened radial bars or ribs 19, also vertical ribs 20 around its interior, to bathe and prevent rotation and consequent scouring of these surfaces by the abrading material 18, but still permitting 'to some extent mobility of the whole.

The ribs or bars 19 and 20 are substitutes, in effect, for the usual renewable lining, of metal or other hard material, required in grinding and pulverizing machines of the present type and not only replace such linmgs but avoid a smooth line of cleavage when the abrading material meets the linings and where little or no effect results from mo tion.

The pressure on the abrading material 18 is in proportion to its depth, being most intense at the bottom, and in all parts, except at the surface, far in excess of what can be attained in tumbling-machines, which for pressure on the grinding medium is no more than the gravity of a thin layer and with water is only the weight of the grinding material in excess of its specific gravity.

The combined water and material to be ground on reaching the bottom of the passage 12 is radially diffused in the horizontal plane 17 at the bottom of driver 2 between two strata of the abrading material, both mobile, that have an intense rinding action by reason of the body of the atter between the arms 14 being in revolution and that below the plane 17 being stirred or agitated mainly on the to or as the distance between the'vanes 14 anc the baffling-vanes 19.

The annular zone 22 between the driver 2 and the walls of the vessel or pan 1 I make of varying width according to the fineness of. the grinding or abrading material used, but in all cases to permit a slow revolution of the general mass contained in this annulus. The coarser the pebbles or grinding material the -wider this space is made, approximately onefifth of the radius of the driver 2.

. The abrading material between the radial arms or vanes 14 being carried around with the driver 2 prevents scour or wear upon these parts of the machine and, as in the case of vessel or pan 1, renders linings unnecessary.

-'In the present machine the material to be ground or pulverized, with the required amount of water, passes down at 12, comin V first in contact with the grinding materia near the center, where motion is slow, then is diffused outward and upward until in liquid form it flows into the annular launder 23 and escapes through the pipe 24 for further treatment by chemicals or otherwise for finally extracting the metalliferous part.

Having thus described the nature and objects of my invention, what I claim asnew, and desire to secure by Letters Patent, is-

1. In a grinding and pulverizing machine, in combination, a cylindrical vessel, a revoluble driver havin radial vanes,- centrally mounted within said vessel, leaving an.an-

' nular space between said driver and the vertical wall of the vessel and a circular space between the driver and the bottom of the vessel, and granular. abrasive material in said annular space and said circular space, and between said vanes, for effecting the grinding function as said abrasive material moves at differential speeds by the operation of the driver, substantially as specified.

2. Ina grinding and ulverizing machine, in combination, a cylin ical vessel, a revoluble driver having radial vanes, centrally mounted within said vessel, leaving an annular space betweensaid driver and the vertical wall of the vessel and a circular space between the driver and the bottom of the vessel, bafl'ling-ribs on the inner face of the vertical wall of the vessel, radial bafilin -bars on the bottom of said vessel, and gran ar abrasive material in said annular space and said circular space, substantially as specified.

3. In a grinding and ulverizing machine, in combination, acylin rical vessel, 'a revoluble driver havin radial vanes, centrallymounted therein, caving an annular space between the two at the sides and a circular spaceat the bottom, a driving-shaft at the center of the driver, a hopper-shaped hub surrounding. said shaft, baffling-bars arranged Within the vertical wall of the vessel and on the floor thereof, and granular abrasive material in said annular and circular spaces, substantially as specified.

4. In agrinding and ulverizing machine, in combination, a cylin rical vessel, a revoluble driver having radial vanes centrally mounted therein, leaving an annular space between the two at the sides and a circular space at the bottom, a driving-shaft at the center of the driver, a hop er-shaped hub surrounding said shaft, a fee ing-chute adj acent to said hopper-shaped hub, bafflingbars arranged on the inner wall and floor of said vessel, an annular trough surrounding said vessel at the top, with'spout, and granular abrasive material in said annular spaceand said circular space, substantially as specified. r

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

BERTRAM HUNT.

i Witnesses JAMES MASON.

ELMER WIoKEs. 

